A brief overview of loop quantum cosmology

Loop quantum cosmology (a symmetry-reduced quantum model of the Universe inspired by loop quantum gravity) extends the inflationary paradigm to the Planck era: the big bang singularity is replaced by a quantum bounce naturally followed by inflation.Testing for these models requires to compute the amount of cosmological perturbations produced in this quantum background and subsequently derives their footprints on the cosmic microwave background.This proceedings proposes a very brief summary of this road from quantum gravity to cosmological observables, focusing on the case of a loop-quantum model of flat FLRW spaces with cosmological perturbations.The background evolution, passing through a bounce, is first presented.The case of cosmic inhomogeneities in a perturbative treatment about a quantum background are then discussed (with an emphasis on two specific theoretical constructions), and there respective predictions in terms of primordial power spectra for the tensor modes are outlined.